The Valve,check, cataloged under National Stock Number 4820-01-441-5755, is classified within Federal Supply Class 4820 (Valves, Nonpowered) of the Valves group. The manufacturer of record is Watts Regulator Company. Government technical data includes 11 specifications, cited from the U.S. Government catalog. The record lists 1 manufacturer part number for this item, enabling identification through both NSN and commercial part number lookups. 1 additional reference document (drawings, advisory and superseded references) is recorded in the U.S. Government catalog. Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4820-01-441-5755 |
| Primary Part Number | 1-1/4-LF909M1QT |
| Item Name | Valve,check |
| FSC / FSG | 4820 / 48 — Valves, Nonpowered |
| Manufacturer | Watts Regulator Company |
| Status | ACTIVE |
| Flow Control Device | BALL |
| Nominal Pipe Size Accommodated | 1.250 INCHES ALL ENDS IN |
| Connection Type | UNTHREADED EXTERNAL PIPE ALL ENDS |
| Style Designator | STRAIGHT THRU FLANGED ENDS |
| Operating Pressure | 175.0 POUNDS PER SQUARE INCH (PSI) MAXIMUM SINGLE RESPONSE LBS |
| Maximum Operating Temp | 180.0 FAHRENHEIT SINGLE RESPONSE DEGF |
| Disk Loading Method | SPRING |
| Media for Which Designed | WATER, FRESH SINGLE RESPONSE |
| Material | COPPER ALLOY FLOW CONTROL DEVICE |
| Material | COPPER ALLOY SEAT |
| Valve Operation Method | AUTOMATIC |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| 1-1/4-LF909M1QT PRIMARY | Watts Regulator Company (USA) |
| Reference | Meaning |
|---|---|
| 909QTM1 1 1/4IN | 5/9 Secondary reference Watts Regulator Company |
NSN 4820-01-441-5755 is a Valve,check, manufactured by Watts Regulator Company, classified under FSC 4820, Valves, Nonpowered. Status: active.
NSN 4820-01-441-5755 has 1 manufacturer part number on file: 1-1/4-LF909M1QT (Watts Regulator Company).
Key specifications for 1-1/4-LF909M1QT: Flow Control Device: BALL; Nominal Pipe Size Accommodated: 1.250 INCHES ALL ENDS IN; Connection Type: UNTHREADED EXTERNAL PIPE ALL ENDS; Style Designator: STRAIGHT THRU FLANGED ENDS. 11 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.